the-star-stuff:

Strange Places on Mars

#1. The image above shows a dune field on the floor of a crater made by an asteroid impact.

#2. This image of layered deposits on a plateau in the Valles Marineris region of Mars was taken in 2007 by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter. The image shows about three-fourths of a mile across. Scientists think the layers contain opaline silica and iron sulfates formed through alteration by acidic water.

#3. This image is of the carbon dioxide ice cap at the south pole of Mars. The pattern is formed by the ice vaporizing. Scientists think that as the ice cap melts from the bottom up, the carbon dioxide turns directly into gas. It flows beneath the ice to openings, eroding the ground below into a spiderlike network of troughs. The flowing gas also carries dust that escapes with it and settles into fan-shaped deposits on top of the ice.

#4. The stripes in this image are linear dunes on the floor of a crater in the Noachis Terra region of Mars. The dark areas are the dunes, and the lighter boulder-strewn lines are between the dunes. This image was taken by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter on Dec. 28, 2009.

#5. This image looks remarkably like groves of trees growing among Martian dunes. But, the trees are an optical illusion. They are actually dark streaks of sediment on the downwind side of the dunes. They were created by escaping gas from the evaporating carbon dioxide ice below. The bottom of the ice melts into vapor and moves toward holes in the ice, carrying dark sediment along with it that is then deposited when the gas escapes.

#6. Scientists have found evidence of iron-bearing sulfates and clay minerals in the exposed areas of this region of the Noctis Labyrinthus formation. A dune field covers some of the ground.

#7. This false-color image looks like it could be of the desert southwest in North America. These gully channels running from a cliff area near the crater rim show typical shapes made by water-carved streams on Earth. The image was taken by the High Resolution Imaging Science Experiment (HiRISE) camera on the Mars Reconnaissance Orbiter.

#8. This image shows an area within Proctor Crater that has both dunes and ripples. The smaller, brighter ridges are ripples made of very fine sand. The larger, darker forms are dunes made of dust from dark volcanic rocks. This image was taken by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter in February 2009. 

Images: NASA/JPL-Caltech/University of Arizona

(via kaleidoscopicmind)